text: Real gases are characterized by their compressibility (z) in the equation PV = znRT. When the pressure P is set as a function of the volume V where the series is determined by set temperatures T, P, and V began to take hyperbolic relationships that are exhibited by ideal gases as the temperatures start to get very high. A critical point is reached when the slope of the graph is equal to zero and makes the state of the fluid change between a liquid and a vapor. The properties of ideal gases contain viscosity, thermal conductivity, and diffusion.